www: avoid uninitialized vars from shadowed Message-IDs

For /all/ (extindex) and like, Message-ID reuse from client
errors or list-injected footers can cause threading weirdness.
Avoid auto-vivification in the mapping table and dereferencing
of unknown messages.

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/PublicInbox/Reply.pm b/lib/PublicInbox/Reply.pm
index 79dd46a7..d96fadfc 100644
--- a/lib/PublicInbox/Reply.pm
+++ b/lib/PublicInbox/Reply.pm
@@ -28,7 +28,7 @@ my $reply_headers = join('|', @reply_headers);
 sub mailto_arg_link {
         my ($ibx, $hdr) = @_;
         my $cc = {}; # everyone else
-        my $to; # this is the From address by defaultq
+        my $to; # this is the From address by default
         my $reply_to_all = 'reply-to-all'; # the only good default :P
         my $reply_to_cfg = $ibx->{replyto};
 
@@ -72,6 +72,7 @@ sub mailto_arg_link {
         my $mid = $hdr->header_raw('Message-ID');
         push @arg, '--in-reply-to='.squote_maybe(mid_clean($mid));
         my $irt = mid_href($mid);
+        add_addrs(\$to, $cc, $ibx->{-primary_address}) unless defined($to);
         delete $cc->{$to};
         if ($obfs) {
                 my $arg_to = $to;